Hot cathode discharge lamps, particularly the fluorescent lamp variety, are widely used in device displays and lighting systems. Upon the application of an applied voltage to the fluorescent tube, a filament heats and releases enough electrons into the tube for the lamp to arc from the voltage applied across opposing cathodes. The length of time in which a fluorescent tube requires in order to establish a sustained arc is dependent upon many variables, one of which is ambient temperature.
At the cold end of the spectrum, the lamp does not want to start, and when it does, the amount of light is restricted because large populations of mercury atoms condense in pools along the inside surface of the cold glass tube. When the tube becomes overheated its efficiency at producing light drops dramatically.
Various schemes have been implemented in the past to accommodate the vagaries of temperature fluctuations. Such schemes typically implore costly, bulky additional components, that are often unacceptable in space constrained applications, such as avionics, medical and computer equipment. Additionally, the use of mechanical devices to control environmental conditions often results in increased maintenance and system failure due to reliability problems with such systems.
Accordingly, an improved system for accommodating temperature fluctuation is needed in certain applications utilizing fluorescent tube light sources.